1. Field of the Invention
The present invention relates to compressors, and more particularly, to compressors that have a cooling structure.
2. Description of the Related Art
Typically, compressors are mounted in vehicles to air-condition the passenger compartments. It is preferable to employ a compressor, the displacement of which is adjustable, to accurately control the temperature in the interior of the vehicle to maintain an environment comfortable to the passengers. A typical compressor has a swash plate, which is mounted tiltably on a rotary shaft. The inclination of the swash plate is controlled by the difference between the pressure in a crank chamber and the suction pressure. The rotation of the swash plate is converted to a reciprocal linear movement of pistons.
Lubricating oil, which lubricates the inside of the compressor, is mixed with the refrigerant gas and flows together with it. The interior of the compressor is sealed by a rubber seal. To cope with deterioration of the lubricating oil and the seal, which is caused by heat produced in the compressor, various measures have been taken in the prior art. One of these measures is described in Japanese Unexamined Utility Model Publication 50-86312. Heat transferring fins are provided on the outer surface of the compressor of this publication.
The 50-86312 publication describes a compressor that transmits the drive force of a vehicle's engine to a rotary shaft through an electromagnetic clutch. Longitudinally extending fins are provided on the outer periphery of the compressor housing. A fan, which sends ambient air to the fins, is mounted on a pulley. Since a solenoid, used for a clutch, is located between the pulley and the compressor housing, the fan is arranged around the periphery of the pulley. The outer diameter of the pulley is about the same as the outer diameter of the housing. Therefore, it is required that the fins project a long distance in the radial direction of the compressor to efficiently cool the fins with the fan. However, such structure enlarges the compressor thus using valuable engine compartment space.